Generally, a cutting tool with an insert fastened thereto is mounted on a machine tool to be used for cutting a workpiece composed of ferrous and nonferrous metals, nonmetal materials, and so on.
The cutting tool includes an insert attaching/detaching apparatus that fastens the insert.
An example of the conventional technology is disclosed in U.S. Pat. No. 8,262,323 which describes an insert attaching/detaching apparatus of a cutting tool including, as illustrated in FIGS. 1 and 2, an insert pocket 20 that receives an insert 24, a clamp arm pocket 22 formed in continuance with the insert pocket 20, a clamp arm 26 received in the clamp arm pocket 22 to retain the insert 24, a first threaded bore 66 formed through the clamp arm 26, a second threaded bore 102 formed on a bottom surface of the clamp arm pocket 22 on the same axis as the first threaded bore 66, and a screw 28 engaged in the first and second threaded bores 66, 102. Specifically, the first and second threaded bores 66, 102 have threads in directions opposite the other, and the threads of the upper end 72 and the lower end 74 of the screw 28 are accordingly formed in opposite directions.
Hereinbelow, a process of attaching or detaching the insert to or from the cutting tool will be described with reference to FIGS. 1 and 2.
First, the process of attaching the insert 24 to the cutting tool will be described. As illustrated in FIG. 1, the insert 24 is seated in the insert pocket 20, after which the upper end 72 of the screw 28 is threadingly engaged by a predetermined amount to the first threaded bore 66 of the clamp arm 26, and then the screw 28 is rotated in a forward direction. As a result, the screw 28 is continuously inserted by the thread engagement with the second threaded bore 102, and at the same time, the clamp arm 26 is moved to the center of the screw 28 such that the insert 24 is securely retained by the clamp arm 26, as illustrated in FIG. 2.
The process of detaching the insert 24 from the cutting tool will now be described below. In the attached state as illustrated in FIG. 2, when the screw 28 is rotated in the reverse direction, the screw 28 is withdrawn from the second threaded bore 102 and at the same time, the clamp arm 26 is moved from the center 76 to the upper end 72. Then as the screw 28 is continuously rotated, as illustrated in FIG. 1, the clamp arm 26 is moved farther away from the insert 24 and the tool holder such that a gap is generated for detachment of the insert 24. Accordingly, the insert 24 is detached through the gap.
However, the conventional insert attaching/detaching apparatus of the cutting tool has a technical configuration that generates a gap for the insert 24 to be attached or detached therethrough, only with the movement of the clamp arm 26 according to rotation of the screw 28. Accordingly, when the insert 24 has an increased cutting edge, this means that it is necessary to rotate the screw 28 more in order to generate the gap. Accordingly, there is a problem that increased time is necessary to attach or detach (i.e., replace) the insert 24.